Yes but everyone uses that to list their guns and ph4t l3wt.

JimBob: Your reasoning is sound. but flawed. Why?

Why is a percentage roll under always inferiour to a roll+bonus roll (I don´t call them roll over for a purpose).

Because of the way the DMs brain works.

In a dice+bonus environment, you do something. You always have a result ("I got a thirteen!") that is communicated to the GM.

Whereas (especially percentage) roll under systems are producing dialogue like this:

"Roll a spot check."
"I failed."

This is the core of the problem!

Boni, Mali, all are of diminishing importance in a roll under environment. Because the player has a target number, or thinks he has. Whereas in dice + bonus, the GM has the target number in his head an can narrate fractional successes.

Of course, that don´t has to be like this, because it´s mathematically interchangable.

But more often than not, in a roll under environment, the GM doesn´t assign a difficulty and modifiers!

And because of this failing of our primate brains:

Roll under mechanisms structurall suck. It takes a concious effort to overcome this structural and basic suckage.

Quote from: SettembriniWhereas (especially percentage) roll under systems are producing dialogue like this:

"Roll a spot check."
"I failed."

This is the core of the problem!

Mmmm, sorry to slam your example but that not how GURPS general works. It more like

GM: "Roll a spot check"
P: "I missed it by 3"
GM: "Ok you didn't see anything"

While not every roll in GURPS you need to know the degree of success or failure, it happens often enough that we just call it out anyway. While other system have Dice+Adds in GURPS the degree of how much you made your roll is the equivalent.

But, Settembrini, as I said, the difference is psychological, not a real one.

In roll-under systems, you get a result too, for example, two less than the target number, or three more than the target number. And in roll-over systems, you can have a "I success/I fail" situation.

Besides, most people immediately apply their modifiers to the target number in a roll over system to figure out what they need to roll.  Which puts us right back to adding the negatives and subtracting the positives again.

Really roll under under a target number that isn't the character's score is the ultimate solution because it gets rid of the whole human limit as maximum difficulty problem.

Quote from: SettembriniBut more often than not, in a roll under environment, the GM doesn´t assign a difficulty and modifiers!

I assume you can quote statistical studies based on a meaningful sample on the roleplaying population?

I've seen these "over-and-under" arguments on forums for years, but never encountered one at the gaming table. Hence, until someone puts up some independently verifiable numbers on the topic, there is no topic.

:toast:

Quote from: the BromgrevI assume you can quote statistical studies based on a meaningful sample on the roleplaying population?

I've seen these "over-and-under" arguments on forums for years, but never encountered one at the gaming table. Hence, until someone puts up some independently verifiable numbers on the topic, there is no topic.

:toast:

Not a lot to talk about then, since the vast majority of statements about RPGs are backed up only with personal experience and opinion.

Of course no one is going to do a serious study on roll under/over.  It would be expensive - even simple academic surveys cost thousands.  Why not share your experiences and talk about how they differ (or not) instead of pointing out the lack of serious evidence one way or the other?

You actually have me curious on the issue of the equivalence of roll-over and roll-under.  There are a couple of situations that have come up from time to time that I wasn't sure if you could model in normal roll-under mechanics.

In Rolemaster, a PC wants to try some hideously difficult stunt.  One that was theoretically possible, but very unlikely to succeed.  Assigning the appropriate difficulty modifier (equivalent to about -300), he then proceeds to roll open-ended three times to barely succeed.  That's about .01% chance of success.  How would you approach this type of occurrence in GURPS?

(I mis-spoke earlier.  CORPS is a roll-under system, but not a typical one, and it does allow for open-ended rolls.)

in GURPS a 3 or 4 always succeeds and an 17 or 18 always succeeds.  I actually like this better because it means that in these rare cases skill has absolutely nothing to do with it.  Just dumb luck.

Though I never use automatic success and failure mechanics in my own systems.  I believe life is harsh.

Quote from: David Johansenin GURPS a 3 or 4 always succeeds and an 17 or 18 always succeeds.  I actually like this better because it means that in these rare cases skill has absolutely nothing to do with it.  Just dumb luck.

Though I never use automatic success and failure mechanics in my own systems.  I believe life is harsh.

I don't care for automatic successes either.  That's why I like open-ended mechanics.  They also give you a lot more room to fiddle with.

Boy...just a little side comment about how I, personally, am a roll-over addict (though investigating Hinterwelts Iridium is challenging me on that), and the place erupts.

I know it's psychological - and I'm pretty sure I never said otherwise - and for the all of the test cases I've looked at (admittedly limited), you can achieve the same results.  It's purely a mindset thing, for me. You know us boorish Americans - we like to beat things.  For me it's that my mind tends toequate success with greater than as opposed to less than. Can I do the other?  Sure, but when you've become used to thinking about something a certain way (a default), it's often a conscious effort to shift to the other.

And the whole point of the "addict" approach was to lessen it's impact on whether over or under was better while still explaining the reason I, personally, dont' play GURPS - though I'd love to find a game with some experienced folks who could help me get into it.

Quote from: David Johansenin GURPS a 3 or 4 always succeeds and an 17 or 18 always FAILS.  I actually like this better because it means that in these rare cases skill has absolutely nothing to do with it.  Just dumb luck.

Though I never use automatic success and failure mechanics in my own systems.  I believe life is harsh.

Fixed your typo to avoid confusion.

Maybe it's because I got started with AD&D where some times you needed to roll high and sometimes you needed to roll low (saves, as I recall were 'low rolls'. Watch as I completely flub this and make a boob of myself... ) but I never really considered much the 'roll high/roll low debate' personally.

I think a couple of years ago I tried to lay out how they work in my own head and realized that there wasn't a real difference or something then moved on. Cue my entry to the online forae of Gaming and suddenly there are wars! WARZ!!!! I tell you... over 'roll over' no, 'roll under'.

I suddenly feel like I"m in a Bud Light Commercial in Bizzaro world.

:what:

Quote from: SpikeMaybe it's because I got started with AD&D where some times you needed to roll high and sometimes you needed to roll low (saves, as I recall were 'low rolls'. Watch as I completely flub this and make a boob of myself... ) but I never really considered much the 'roll high/roll low debate' personally.

I think a couple of years ago I tried to lay out how they work in my own head and realized that there wasn't a real difference or something then moved on. Cue my entry to the online forae of Gaming and suddenly there are wars! WARZ!!!! I tell you... over 'roll over' no, 'roll under'.

I suddenly feel like I"m in a Bud Light Commercial in Bizzaro world.

:what:

I have no opinion as to which way is better.  There are systems I like that use both approaches.  I just know that when I discover a system with a roll over approach (especially with an open-ended mechanic), that it's a "plus" for me.

Quote                       
                                                But, Settembrini, as I said, the difference is psychological, not a real one.

That´s true. but psyche is the larger godess in that arena.

Show me a GM who asks for your exact margin of failure in a roll-under precentage environment.